This invention relates to a feeder for expelling thick viscous printing ink from ink storage containers, primarily cylindrical cans, directly into an ink fountain of a printing press.
The ink consumption in a modern, high speed lithographic press can be considerable. Little attention has been given to providing assistance to the pressman in keeping an adequate level of ink in the pan of press's ink fountain.
Most lithographic printing inks are quite viscous, comparable to thick molasses or a heavy grease. As a result, such ink does not flow readily and requires considerable pumping pressure if some form of pump is used to transfer the ink from a storage container. Typically, inks used in printing job shops are supplied in sealed cylindrical cans of about five pound capacity, although the exact diameter of such cans may vary somewhat from one supplier to another. A number of reasons dictate this such as convenience in storage and handling, ability to keep the ink under seal until it is ready for use, and frequent need to change colors in different relatively short runs that are common to such shops.
As a result, a commonly employed method for keeping correct level of ink in a press fountain is for the pressman to open a can as needed and, as he observes a need for more ink in the fountain, scoop a large mass of the thick viscous ink from the can, using a wide spatula type knife, and "wipe" it into the ink fountain pan or against the fountain roller of the ink fountain if the press is momentarily not operating. Where larger presses and/or longer runs are involved, it may be desirable to use some sort of pump (either manual or motor operated) under control of the pressman to transfer ink from a can to the fountain pan.
When such presses are running longer jobs, and using the same color ink in greater quantities, on the same equipment, the frequent attendance of the pressman to this ink supply task becomes something of a burden. Any arrangement for making his job simpler at this time, or requiring less repeated attendance to the ink fountain, enables him to spend more uninterrupted time concentrating on other tasks such as washing up or making ready another press in the shop, or attending to other necessary duties.
No two jobs are alike in ink demand, so any equipment for partially automated ink feeding must be capable of adjusting the ink feed rate to keep up with, but not exceed, the printing press's utilization of the ink. In addition, the feeder equipment should be able to sense and inform the operator that an ink can in use has been depleted and should be replaced.